Earlier this week, in a story about the Olympic sport of curling, we said curlers sweep the ice to give their team's stone more momentum. Well, that's not quite right, as many listeners pointed out. In fact, sweeping the ice melts it slightly. And that reduces the friction against the curling stone, allowing it to go farther.

ROBERT SIEGEL, HOST:

Our other correction comes from Roger Day of the Math Department at Illinois State University. He wrote to correct something I said in my story about light bulbs. I said that the estimated life of a light bulb isn't a minimum, it's a mean. When half of a test group of bulbs dies, that is the estimated life.

Well, Professor Day wrote to say: This time measure, of course, is the median, the physical middle of a data set. A mean couldn't have been computed until all bulbs had burnt out.

Well, he is of course correct. But I had in mind a more generic definition of the term mean, such as the one that Merriam-Webster offers up: A middle point between two things.

CORNISH: Now to your letters. On Monday, we aired a story about rock salt shortages across the country. It turns out it's not easy stockpiling salt in the summer, when it's available and cheap. Most local governments just don't have the room to house it.

Well - Todd Abronowitz of Wylie, Texas writes: The next story was about the empty big box retail outlets, and a comment was made in that story about all of the space that is available and how to re-purpose the buildings. Was it just me who can put two and two together?

SIEGEL: Meanwhile, in balmy Great Falls, Montana, listener Greg Muir writes this: Put all of those Easterners on a bus and send them out here to the banana belt; have been enjoying small amounts of snow and warmer temperatures. We have no problems with sunny days and temperatures frequently in the 30s and 40s. Oops, looks like a half an inch of snow may be coming. Have to go locate my winter survival book.

CORNISH: Our last letter comes from Toby Baker of Windsor, Colorado. After the winter we've had, Baker writes that ice walking should be recognized as an Olympic sport. As she describes it, ice walking can be done in pairs. In this case with Molly, her golden retriever. The goal, just stay vertical in the rink.

SIEGEL: Also known as a driveway.

CORNISH: Or grocery store parking lot.

SIEGEL: Without having to call 911.

CORNISH: Here's Ms. Baker in her own words.

TOBY BAKER: During our performance, there is no looking up from the ice, no connection with the audience, no eye-contact with the judges. Nope, one glance away, one break in ice concentration and the results are unexpected, Hawaii 5-Os, double mamma mia, triple grab move mumus, LOL jumps, formally known as disasters and help plaster cast.

(SOUNDBITE OF A BARKING DOG)

UNIDENTIFIED MAN: Good girl...

CORNISH: Thanks to Toby Baker and that special guest appearance from Molly, her golden retriever. And thanks to everyone else who wrote in. Please, keep your letters coming. Go to NPR.org and click on Contact.

(SOUNDBITE OF SONG, "SIDEWALKS AND GRAND")

MATT AND KIM: (Singing) Ice melts around me. Watered down me it will, watered down it will never be. Ice melts around me. Together we will, together we will make it freeze. Searching for my left shoe in a... Transcript provided by NPR, Copyright NPR.